A current topic in the 3GPP (Third Generation Partnership Project) standardization groups is the further development of UMTS (Universal Mobile Telecommunications System) towards a mobile radio communication system optimized for packet data transmission by improving the system capacity and the spectral efficiency. In 3GPP, the activities in this regard are summarized under the general term LTE for “Long Term Evolution”. The aim is amongst others to increase the maximum net transmission rate significantly in future, namely to 300 Mbps in the downlink transmission direction and to 75 Mbps in the uplink transmission direction.
For the transmission of data in uplink transmission direction, a closed-loop power control is conventionally carried out for the physical channels PUSCH (Physical Uplink Shared Channel) and PUCCH (Physical Uplink Control Channel), i.e. the eNodeB (evolved NodeB) transmits TPC (Transmit Power Control) commands to the UE (User Equipment) on which the transmit power of PUSCH and PUCCH in a subframe are adjusted. Main purposes of the uplink transmission direction closed-loop power control are usually to compensate path-loss and achieve a given SINR (Signal-to-Interference Noise Ratio) target for the respective physical channels.
In fact, the setting of the UE transmit power for PUSCH and PUCCH transmission in a subframe does not only depend on the TPC command but may also depend on mobile radio cell-specific and UE-specific parameters. The cell-specific parameters are usually broadcast by an eNodeB to all UEs in a mobile radio cell via system information. The UE-specific parameters are signaled by an eNodeB to a UE in a dedicated RRC (Radio Resource Control) message, e.g. during channel establishment procedure.
Regarding the cell-specific power control parameters, there may be an issue if these parameters need to be updated, e.g. due to adaptation of the uplink transmission direction power control operation by the communication network depending on the traffic load in the mobile radio cell. However, the current mechanism for notification and update of system information as specified is inefficient for uplink transmission direction power control purposes as the duration between the decision by the communication network to change the system information and its usage can be relatively long. Thus, for a relatively long time, uplink transmission direction power control operation may be performed based on outdated parameters that would result in severe performance degradation in the uplink.
Therefore, there is a need for an optimization of the current mechanism for notification and update of uplink transmission direction power control related system information.